Composite Oxide-Silicon TFT Structure for Mobility and Stability
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Solution Overview
Problem
Current thin film transistors face challenges in achieving a balance between high mobility, stability, and low manufacturing costs, with amorphous silicon transistors having low mobility, polycrystalline silicon transistors being costly and difficult to manufacture uniformly, and oxide semiconductor transistors having low stability and mobility.
Innovation Solution
A thin film transistor design incorporating both a silicon semiconductor layer and an oxide semiconductor layer, with specific overlapping configurations and doping processes to enhance mobility and stability, allowing for improved switching properties and large s-factor performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If amorphous silicon is used as the active layer material, then manufacturing time is short and manufacturing cost is low, but electron mobility is low and threshold voltage changes
Solution Approach 1:
The patent uses a composite active layer structure combining amorphous silicon and oxide semiconductor materials. The amorphous silicon layer provides fast deposition and low cost, while the oxide semiconductor layer provides high stability and mobility. This composite structure resolves the contradiction by integrating the advantages of both materials while mitigating their individual weaknesses.
2Reliability
If polycrystalline silicon is used as the active layer material, then electron mobility is high and stability is great, but manufacturing cost increases due to additional crystallization steps and high temperature processing
Solution Approach 1:
The patent replaces the expensive polycrystalline silicon structure with a composite of amorphous silicon and oxide semiconductor. This combination achieves comparable or superior stability without requiring high-temperature crystallization processes, thereby reducing manufacturing complexity and cost while maintaining high electron mobility.
Solution Approach 2:
The patent changes the material composition parameters of the active layer, using oxide semiconductor with specific oxygen content to achieve high stability and mobility. This parameter change allows obtaining polycrystalline-like performance at lower temperatures and with simpler processes.
3Ease of manufacture
If oxide semiconductor is used as the active layer material, then manufacturing cost is low and transparency is achieved, but electron mobility is low and stability is low
Solution Approach 1:
The patent creates a composite active layer where oxide semiconductor is combined with amorphous silicon. The oxide semiconductor component provides low-cost deposition and transparency, while the amorphous silicon component enhances electron mobility and stability. This composite approach resolves the limitations of pure oxide semiconductor while preserving its cost and transparency advantages.
Data Source
AI summary
Disclosed are a thin film transistor, a display apparatus comprising the thin film transistor, and a method for manufacturing the thin film transistor. The thin film transistor comprises an active layer, and a gate electrode spaced apart from the active layer and configured to have at least a portion overlapped with the active layer, wherein the active layer includes a silicon semiconductor layer, and an oxide semiconductor layer which contacts the silicon semiconductor layer, wherein at least a portion of the silicon semiconductor layer and at least a portion of the oxide semiconductor layer are overlapped with the gate electrode.